1. Field of the Invention
The present invention relates to a centrifugal fan, and particularly, the present invention relates to a centrifugal fan that is used for cooling electric products and electronic devices.
2. Background Art
In recent years, the electronic devices are made compact and are provided with high performance. In accordance with this, a cooling fan that is mounted in the electronic device is required to be downsized. In response to downsizing of the electronic device, parts are made highly integrated. Thus a density in a chassis of the device becomes high. Therefore, the cooling fan that is mounted in the electronic device is required to have a high static pressure and large air volume.
Conventionally, a structure of arranging a compact cross flow fan on a heat sink for heat release has been known. However, the compact cross flow fan cannot acquire a high static pressure.
In addition, conventionally, a centrifugal fan that is made thin in an axial direction by making a radius of an impeller shorter than a length of the centrifugal fan in an axial direction has been known. However, in order to acquire required air volume and static pressure, a sectional area orthogonal to an axis is made larger, so that further downsizing is required.
Further, in the fan that is mounted in the electronic device, a noise should be decreased.
A first object of the present invention is to provide a downsized centrifugal fan having a high static pressure and an increased air volume, a second object of the present invention is to provide a downsized centrifugal fan, and a third object of the present invention is to provide a centrifugal fan having noise decreased.